A communication system is used to communicate data between two, or more, separate positions, or entities. In a minimal implementation, a communication system is formed of a first communication station forming a sending station and a second communication station, forming a receiving station. The communication stations are interconnected by way of a communication channel. Data to be communicated by the first communication station is converted, if necessary, into a form to permit its communication upon the communication channel to the second communication station. And, the second communication station operates to detect the data communicated thereto and to recover the informational content thereof.
A wide variety of different types of communication systems have been developed and are regularly utilized to effectuate communication of the data between the communication stations. And, new types of communication systems, as well as improvements to existing communication systems, have been made possible as a result of advancements in communication technologies.
A radio communication system is exemplary of a type of communication system that has benefited from advancements in communication technologies. In a radio communication system, the communication channel formed between the communication stations operable therein is defined upon a radio link. As a radio link is utilized upon which to define the communication channel, the need otherwise to utilize a wireline connection extending between the communication stations to define communication channels is obviated. Reduced infrastructure costs are therefore generally associated with radio communication systems. And, a radio communication system can be implemented to form a mobile communication system.
A cellular communication system is exemplary of a radio communication system that has been made possible due to advancements in communication technologies. A cellular communication system provides for radio communications with mobile stations to permit the telephonic communication to be effectuated therefrom. A cellular communication system is installed throughout a geographical area through the use of spaced-apart base transceiver stations, each of which define a portion of the geographical area, referred to as a cell. When a mobile station is within the cell defined by a base transceiver station, communications are generally effectuable with the base transceiver station that defines the cell.
Communications are handed-off between successive base transceiver stations when the mobile station travels out of one cell and into other cells, defined by others of the base transceiver stations. Through appropriate positioning of the base transceiver stations and permitting communication hand-offs to successive ones of the base transceiver stations, only relatively low-powered signals need to be generated during telephonic communications between the mobile station and the base transceiver station. As a result, the same channels can be used at different locations of the same cellular communication system. Relatively efficient usage of the frequency spectrum allocated to a cellular communication system is thereby possible.
Cellular communication systems are constructed, generally, to operate according to an operational specification set forth by a standard body, such as the EIA/TIA. Successive generations of cellular communication systems, incorporating technological advancements, as available, have been defined by operational specifications. First-generation and second-generation systems have achieved significant levels of usage, and installation of third-generation and successor-generation systems have been proposed.
Third-generation systems provide for multi-rate data communication services that utilize packet-formatted data. A so-called CDMA 2000 standard is an exemplary third-generation communication system, intended to provide such multi-data rate communication services utilizing communication of packet-formatted data.
Structure, and functionality, defined in the proposed CDMA 2000 system is defined in terms of logical layers. Other communication systems are analogously defined in such terms. In a CDMA 2000 system, multiple formatting layers are set forth. And, in particular, an RLP (radio link protocol) layer is positioned above a physical layer. The RLP layer utilizes an RLP retransmission scheme while the physical layer utilizes an HARQ (hybrid-automatic request) retransmission scheme. The retransmission schemes define retransmission protocols by which a receiving station selectively requests retransmission of a packet of data upon failure of successful delivery of the data packet to the receiving station. Because retransmission schemes are provided for separate layers, retransmission requests might be sent by both the RLP layer as well as at the physical layer. Such redundancy of retransmission requests are counterproductive to a goal of efficient radio spectrum usage.
A manner is needed by which to reduce the possibility that the multiple layers of a receiving station might redundantly request retransmission of a data packet.
It is in light of this background information related to communications in a packet radio communication system that the significant improvements of the present invention have evolved.